# frozen_string_literal: true
# rubocop:disable Style/RedundantFetchBlock
#
require 'spec_helper'

RSpec.describe ProtectedBranches::CacheService, :clean_gitlab_redis_cache do
  subject(:service) { described_class.new(project, user) }

  let_it_be(:project) { create(:project) }
  let_it_be(:user) { project.first_owner }

  let(:immediate_expiration) { 0 }

  describe '#fetch' do
    it 'caches the value' do
      expect(service.fetch('main') { true }).to eq(true)
      expect(service.fetch('not-found') { false }).to eq(false)

      # Uses cached values
      expect(service.fetch('main') { false }).to eq(true)
      expect(service.fetch('not-found') { true }).to eq(false)
    end

    it 'sets expiry on the key' do
      stub_const("#{described_class.name}::CACHE_EXPIRE_IN", immediate_expiration)

      expect(service.fetch('main') { true }).to eq(true)
      expect(service.fetch('not-found') { false }).to eq(false)

      expect(service.fetch('main') { false }).to eq(false)
      expect(service.fetch('not-found') { true }).to eq(true)
    end

    it 'does not set an expiry on the key after the hash is already created' do
      expect(service.fetch('main') { true }).to eq(true)

      stub_const("#{described_class.name}::CACHE_EXPIRE_IN", immediate_expiration)

      expect(service.fetch('not-found') { false }).to eq(false)

      expect(service.fetch('main') { false }).to eq(true)
      expect(service.fetch('not-found') { true }).to eq(false)
    end

    context 'when CACHE_LIMIT is exceeded' do
      before do
        stub_const("#{described_class.name}::CACHE_LIMIT", 2)
      end

      it 'recreates cache' do
        expect(service.fetch('main') { true }).to eq(true)
        expect(service.fetch('not-found') { false }).to eq(false)

        # Uses cached values
        expect(service.fetch('main') { false }).to eq(true)
        expect(service.fetch('not-found') { true }).to eq(false)

        # Overflow
        expect(service.fetch('new-branch') { true }).to eq(true)

        # Refreshes values
        expect(service.fetch('main') { false }).to eq(false)
        expect(service.fetch('not-found') { true }).to eq(true)
      end
    end

    context 'when dry_run is on' do
      it 'does not use cached value' do
        expect(service.fetch('main', dry_run: true) { true }).to eq(true)
        expect(service.fetch('main', dry_run: true) { false }).to eq(false)
      end

      context 'when cache mismatch' do
        it 'logs an error' do
          expect(service.fetch('main', dry_run: true) { true }).to eq(true)

          expect(Gitlab::AppLogger).to receive(:error).with(
            {
              'class' => described_class.name,
              'message' => /Cache mismatch/,
              'project_id' => project.id,
              'project_path' => project.full_path
            }
          )

          expect(service.fetch('main', dry_run: true) { false }).to eq(false)
        end
      end

      context 'when cache matches' do
        it 'does not log an error' do
          expect(service.fetch('main', dry_run: true) { true }).to eq(true)

          expect(Gitlab::AppLogger).not_to receive(:error)

          expect(service.fetch('main', dry_run: true) { true }).to eq(true)
        end
      end
    end
  end

  describe '#refresh' do
    it 'clears cached values' do
      expect(service.fetch('main') { true }).to eq(true)
      expect(service.fetch('not-found') { false }).to eq(false)

      service.refresh

      # Recreates cache
      expect(service.fetch('main') { false }).to eq(false)
      expect(service.fetch('not-found') { true }).to eq(true)
    end
  end

  describe 'metrics' do
    it 'records hit ratio metrics' do
      expect_next_instance_of(Gitlab::Cache::Metrics) do |metrics|
        expect(metrics).to receive(:increment_cache_miss).once
        expect(metrics).to receive(:increment_cache_hit).exactly(4).times
      end

      5.times { service.fetch('main') { true } }
    end
  end
end
# rubocop:enable Style/RedundantFetchBlock